Attachment for distributing rock dust

ABSTRACT

A hopper having a pair of generally rectangular side walls and front and rear walls with an arcuate semi-circular edge portion is positioned in overlying relation with a generally conical exhaust duct portion of a blower. The front and rear wall lower edge portions have substantially the same configuration as the duct outer surface to thus form a substantially fluid tight connection therebetween. The side walls have lower inturned portions abutting the outer surface of the duct portion to thus form a receiver for rock dust positioned on the outer surface of the exhaust duct. A cover member is hingedly secured to the upper edge of the rear wall and is arranged to be locked in place to form a relatively fluid tight enclosure within the hopper. The exhaust duct has an upper air inlet opening with an air directing tube secured thereto through which air from the internal portion of the duct is arranged to flow into the hopper and fluidize the rock dust within the hopper and direct the rock dust toward the lower portions of the hopper. The exhaust duct has a pair of elongated air inlet openings adjacent the lower portions of the hopper. Air flow tubes extend through the inlet opening into the inner portion of the hopper and are arranged to introduce a portion of the air stream flowing through the exhaust duct into the lower portions of the hopper. Outlet openings are provided in the duct adjacent the pair of air inlet openings and guide tubes surround the outlet openings and extend into the duct. The air flow tubes terminate within the hopper adjacent the outlet openings in the duct. The air as it leaves the air flow tubes entrains rock dust in the air stream and the air entrained rock dust flows through the outlet openings into the stream of exhaust air flowing through the exhaust duct. Flow control members are secured to the walls of the duct and are arranged to be positioned in overlying relation with the outlet openings formed in the duct to thereby control the amount of rock dust discharged from the hopper through the outlet openings into the air stream flowing through the duct.

Benedetti ay 7, 1974 ATTACHMENT FOR DISTRIBUTING ROCK inturned portions abutting the outer surface of the DUST Inventor: Albert L. Benedetti, R.D. No. 2, Rayland, Ohio 43943 Primary Examiner-Evon C. Blunk Assistant Examiner-W. Scott Carson Attorney, Agent, or FirmStanle y J. Price, Jr.

[57] ABSTRACT A hopper having a pair of generally rectangular side walls and front and rear walls with an arcuate semicircular edge portion is positioned in overlying relation with a generally conical exhaust duct portion of a blower. The front and rear wall lower edge portions have substantially the same configuration as the duct outer surface to thus form a substantially fluid tight connection therebetween. The side walls have lower duct portion to thus form a receiver for rock dust positioned on the outer surface of the exhaust duct. A cover member is hingedly secured to the upper edge of the rear wall and is arranged to be locked in place to form a relatively fluid tight enclosure within the hopper. The exhaust duct has an upper air inlet opening with an air directing tube secured thereto through which air from the internal portion of the duct is arranged to flow into the hopper and fluidize the rock dust within the hopper and direct the rock dust toward the lower portions of the hopper. The exhaust duct has a pair of elongated air inlet openings adjacent the lower portions of the hopper. Air flow tubes extend through the inlet opening into the inner portion of the hopper and are arranged to introduce a portion of the air stream flowing through the exhaust duct into the lower portions of the hopper. Outlet openings are provided in the duct adjacent the pair of air inlet openings and guide tubes surround the outlet openings and extend into the duct. The air flow tubes terminate within the hopper adjacent the outlet openings in the duct. The air as it leaves the air flow tubes entrains rock dust in the air stream and the airentrained rock dust flows through the outlet openings into the stream of exhaust air flowing through 'the' exhaust duct. Flow control members are secured to the walls of the duct and are arranged to be positioned in overlying relation with the outlet openings formed in the duct to thereby control the amount of rock dust discharged from the hopper through the outlet openings into the air stream flowing through the duct.

6 Claims, 4 Drawing Figures 1 ATTACHMENT FOR DISTRIBUTING ROCK DUST BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to an apparatus for distributing rock dust in an air stream and more particularly to a rock dust distributor attachment for an exhaust blower.

2. Description of the Prior Art U.S. Pat. No. 3,333,896 describes a method and apparatus for rock dusting during coal mining operations in which a bin is secured to a mining machine and is connected by means of a venturi to a compressor. A portion of the air from the compressor is directed into the bin and fluidizes the rock dust therein. The rock dust is arranged toflow into the throat of the venturi where it is admixed with the air supplied from the compressor and the entrained rock dust is mixed with the ventilating air flowing away from the working face. The apparatus disclosed requires a separate compressor, a storage bin and piping including a venturi section for entraining the rock dust in the air.

There have been other attempts to introduce rock dust into the fan discharge stream of exhaust blowers by mounting a hopper on the fan housing. This, as is stated in an article entitled Face Ventilation With Continuous Mining," in a publication entitled Mechanization of September, 1962, has proven to be fairly successful, but the rock dust was fed solely by the vibration of the fan housing and some difficulty was encountered in maintaining a steady flow of rock dust. In order to overcome this difficulty, the company had ordered two coaxial-motor fans equipped with a rock dust hopper from which the rock dust will be fed automatically and continuously into the fan discharge stream by a star feeder. Even with the above apparatus for distributing rock dust, additional components, such as star feeders and the like, are required to mix the rock dust with the air for proper entrainment and distribution.-

There is a needfor relatively simple apparatus that may be utilized with existing equipment, such as conventional exhaust blowers, and will efficiently distribute the rock dust in the air stream to reduce the hazards of depositing layers of coal dust in the haulageways or cross-cuts therebetween.

SUMMARY OF THE INVENTION In accordance with the invention, there is provided an improved rock dust distributor attachment that includes a hopper having a pair of side walls, a front wall,

a rear wall and a top wall. The front and rear walls have arcuate bottom edge portions that are positioned over the outer arcuate surface of an exhaust blower duct and have substantially the same configuration as the duct outer arcuate surface. The walls of the hopper and the outer surface of the exhaust duct form a receiver for rock dust. A first air inlet means is provided to introduce-air into the hopper lower portion and a rock dust outlet means is provided adjacent to the first air inlet means through which rock dust is conveyed into the blower exhaust duct by the airflowing into the hopper through the first air inlet means. A flow control means is provided to control the amount of rock dust discharged through-the rock dust outlet means into the air flowing through the exhaust duct. A second air inlet means may be provided adjacent the upper portion of the hopper to direct the rock dust in the hopper toward the rock dust outlet means.

The improved rock dust distributor utilizes a portion of the air flowing through the exhaust duct as the conveying means for the rock dust and other sources of air under pressure from separate apparatus, such as compressors or the like, are not required. Complicated feeder devices, such as star feeders and the like, are eliminated with the improved rock dust distributor of this invention. A simple plate like control device may be adjusted to regulate the size of the rock dust outlet aperture and thus accurately control the amount of rock dust discharged into the air stream in the exhaust duct.

Accordingly, the principal object of this invention is to provide a rock dust distributor attachment for an exhaust blower that utilizes a portion of the air flowing through the blower exhaust ductas the conveying means for the rock dust.

Another object of this invention is to provide a rock dust distributor attachment that utilizes the outer surface of a blower exhaust duct as a portion of the receiver for the rock dust.

These and other objects and advantages of this invention will be more completely disclosed and described in the following specification, the accompanying drawings and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view in side elevation of an exhaust blower with the improved rock dust distributor attachment positioned thereon.

FIG. 2 is an enlarged view in side elevation, illustrating the exhaust duct portion of the blower with the rock dust distributor attachment positioned thereon. The lower portion of the rock dust attachment is broken away to illustrate the air inlet and outlet openings in the exhaust duct.

FIG. 3 is a top plan view of the exhaust duct with the rock dust distributor attachment positioned thereon and illustrating the air inlets into the hopper and the manner in which the rock dust is discharged from the hopper. into the air stream within the exhaust duct.

FIG. 4 is a view in front elevation of the exhaust duct with the rock dust distributor attachment positioned thereon.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 16 into the body portion 20 of blower 10 and through the suction blowers mounted therein. The dust laden air is then discharged from the body portion 20 through a second flexible conduit 22. The flexible conduit 22 is connected to a metallic exhaust duct 26 that is, in turn, rigidly connected to the blower body portion 20. As is illustrated in FIG. I, the exhaust duct 26 has a cylindriby the numeral 32 is positioned on top of the exhaust duct 26 and has a supply of rock dust therein that is controllably introduced into the stream of air flowing through the exhaust duct 26.

Referring to FIGS. 2, 3 and 4, the construction of the attachment 32 is illustrated in detail and includes a pair of generally rectangular side walls 34 and 36, front wall 38 and rear wall 40. The side walls 34 and 36 are of a generally rectangular configuration and have upper edge portions 42 and 44 and lower edge portions 46 and 48. Horizontal base members 50 and 52 are connected to the side wall lower edge portions 46 and 48 and extend inwardly therefrom. The base members 50 and 52 abut .the outer surface 54 of exhaust duct 26. The front and rear walls 38 and 40 have substantially the same configuration with upper edge portions 56 and bottom arcuate edge portions 58. The bottom edge portions 58 have substantially the same configuration as the outer surface 54 of duct 26. With this arrangement, the walls of the rock dust distributor attachment 32 form a generally saddle like receiver or hopper that is positioned on the upper curved outer surface 54 of duct 26. The duct outer surface 54 thus forms the bottom wall of the hopper in which the rock dust is stored.

As best illustrated in FIGS. 2 and 3, the duct conical surface 30 has a generally elliptical opening 60 therethrough with an air directing tube 62 surrounding the opening 60. The air directing tube 62 is positioned with The control members 86 and 88 are arranged to be positioned in overlying relation with the outlet openings 86 and 88 to control the flow of entrained rock dust therethrough. To obtain maximum flow of rock dust into the air stream within exhaust duct 26 the control members 94 and 96 are moved to uncover the openings 86 and 88. To reduce the flow through the opening the control members 94 and 96 are moved to partially cover and thus reduce the effective size of openings 86 and 88.

Outlet ends 82 and 84 of air tubes 70 and 72 terminate adjacent the outlet openings 86 and 88 and the air flowing through air tubes 70 and 72 by means of a venturi type action entrains rock dust in the hopper 32 and conveys the rock dust through openings 86 and 88. The entrained rock dust is directed by guide tubes 90 and 92 into the central portion of the air stream within exhaust duct 26 to be admixed with the coal dust in the air stream prior to discharge through the flexible conduit 22.

The attachment 32 has a cover member 102 that is hingedly secured along one edge to the rear wall 38 by hinges 104 and a lock mechanism 106 secures the cover to the front wall 40. A handle 108 is provided for cover 102 and handles 1 10 are provided for the attachment 32.

With this arrangement,'it is now possible by means of the above described attachment to efficiently and effectively distribute rock dust in a dust laden air stream flowing through a conventional exhaust blower without the use of separate motors, compressors, star feeders the lower portions of the hopper 32. The air flowing through tube 62' thus provides a positive pressure within the hopper 32 andurges the rock dust down- 4 wardly toward the lower portions of the hopper 32.

F I08. 2 and 3 also illustrate a pair of elongated openings 66 and 68 located on opposite sides of the duct 26 through which curved air flow tubes 70 and 72 extend into the innerportion of the hopper 32. Air channel tubes 74 and 76, are secured to the inner wall of the duct 26 and surround the inlet ends 78 and 80 of air flow tubes 70 and 72. The air flow tubes 70 and 72 have outlet end portions 82 and 84 that terminate within the hopper 32. The exhaust duct cylindrical portion 28 has a pair of outlet openings 86, and 88 adjacent to the reings 86 and 88. Guide tubes 90 and 92 surround the outlet openings 86 and 88 and extend inwardly toward the axis of the exhaust duct 26 to direct the air entrained rock dust discharged through openings 86 and 88 into the main portion of the air stream flowing through the exhaust duct 26.

A pair of plate like control members 94 and 96 are secured to the outer surface 54 of duct 26 by means of bolts 98 extending through elongated apertures 100.

and the like. I

According to the provisions of the patent statutes, l have explained the principle, preferred construction and mode of operation of my invention and have illustrated and described what I now consider to represent its best embodiments. However, it should be understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.

I claim:

1. A rock dust distributor attachment comprising,

a hopper member having a pair of side walls, a front wall, a rear wall and a top wall,

said front wall and rear wall having arcuate bottom edge portions arranged to be positioned over the outer arcuate surface of an exhaust blower duct, said front and rear wall bottom edge portions having substantially the same configuration as said duct outer arcuate surface to form a substantially fluid tight connection therebetween with said duct arcuate outer surface forming a bottom wall for said hopper, said hopper front and rear walls having depending leg portions extending around said exhaust blower duct and tenninating at a location below the axis of said duct,

first air inlet means arranged to introduce air into the hopper from the exhaust duct at a location adjacent the hopper lower portion,

said first air inlet means including a pair of apertures in said exhaust duct adjacent the bottom of said hopper front and rear wall depending leg portions,

air flow directing tubes extending through said pair of apertures, each of said tubes having an air inlet portion extending into the inner portion of said duct and an air outlet portion terminating in said hopper,

rock dust outlet means positioned adjacent to said first air inlet means, said rock dust outlet means arranged to introducerock dust into the internal portion of said exhaust duct,

said rock dust outlet means including a pair of outlet apertures in said exhaust duct adjacent to the bottom of said hopper front and rear wall depending leg portions, each of said air flow directing tubes having said air outlet portions positioned adjacent to'one of said outlet apertures so that air flowing through said tubes conveys rock dust through said outlet apertures into said exhaust duct, and

rock dust directing tubes surrounding said outlet apertures and extending into said exhaust duct, said rock dust directing tubes arranged to direct rock dust from said hopper toward the center of said duct.

2. A rock dust distributor attachment as set forth in claim 1 which includes,

second air inlet means arranged to introduce air into the upper portion of said hopper from the exhaust duct at a location adjacent the upper portion of said hopper so that air flowing into said hopper through said second air inlet means directs the rock dust in said hopper toward said rock dust outlet means.

3. A rock dust distributor attachment asset forth in claim 2 in which said second air inlet means includes,

an aperture in said exhaust blower duct and a tube surrounding said aperture and extending into said exhaust duct. 4. A rock dust distributor attachment as set forth in claim 1 which includes,

flow control means positioned in overlying relation with said outlet means and arranged to control the amount of rock dust discharged through said rock dust outlet means. 5. A rock dust distributor attachment as set forth in claim 4 in which,

said control means' includes a plate member secured to said duct outer surface, and means to adjust said plate member on said duct outer surface to regulate the effective size of said outlet means. 6. A rock dust distributor attachment as set forth in claim 1 in which,

said hopper side walls each having inturned bottom edge portions extending toward the outer surface of said duct, said inturned bottom portions having edge portions abutting said duct outer surface and'forming a portion of the receiver. 

1. A rock dust distributor attachment comprising, a hopper member having a pair of side walls, a front wall, a rear wall and a top wall, said front wall and rear wall having arcuate bottom edge portions arranged to be positioned over the outer arcuate surface of an exhaust blower duct, said front and rear wall bottom edge portions having substantially the same configuration as said duct outer arcuate surface to form a substantially fluid tight connection therebetween with said duct arcuate outer surface forming a bottom wall for said hopper, said hopper front and rear walls having depending leg portions extending around said exhaust blower duct and terminating at a location below the axis of said duct, first air inlet means arranged to introduce air into the hopper from the exhaust duct at a location adjacent the hopper lower portion, said first air inlet means including a pair of apertures in said exhaust duct adjacent the bottom of said hopper front and rear wall depending leg portions, air flow directing tubes extending through said pair of apertures, each of said tubes having an air inlet portion extending into the inner portion of said duct and an air outlet portion terminating in said hopper, rock dust outlet means positioned adjacent to said first air inlet means, said rock dust outlet means arranged to introduce rock dust into the internal portion of said exhaust duct, said rock dust outlet means including a pair of outlet apertures in said exhaust duct adjacent to the bottom of said hopper front and rear wall depending leg portiOns, each of said air flow directing tubes having said air outlet portions positioned adjacent to one of said outlet apertures so that air flowing through said tubes conveys rock dust through said outlet apertures into said exhaust duct, and rock dust directing tubes surrounding said outlet apertures and extending into said exhaust duct, said rock dust directing tubes arranged to direct rock dust from said hopper toward the center of said duct.
 2. A rock dust distributor attachment as set forth in claim 1 which includes, second air inlet means arranged to introduce air into the upper portion of said hopper from the exhaust duct at a location adjacent the upper portion of said hopper so that air flowing into said hopper through said second air inlet means directs the rock dust in said hopper toward said rock dust outlet means.
 3. A rock dust distributor attachment as set forth in claim 2 in which said second air inlet means includes, an aperture in said exhaust blower duct and a tube surrounding said aperture and extending into said exhaust duct.
 4. A rock dust distributor attachment as set forth in claim 1 which includes, flow control means positioned in overlying relation with said outlet means and arranged to control the amount of rock dust discharged through said rock dust outlet means.
 5. A rock dust distributor attachment as set forth in claim 4 in which, said control means includes a plate member secured to said duct outer surface, and means to adjust said plate member on said duct outer surface to regulate the effective size of said outlet means.
 6. A rock dust distributor attachment as set forth in claim 1 in which, said hopper side walls each having inturned bottom edge portions extending toward the outer surface of said duct, said inturned bottom portions having edge portions abutting said duct outer surface and forming a portion of the receiver. 